I slap with all four fingers (thumb, index, middle and ring fingers). This greatly enhances the possibilities of slapping. You can slap four string chords, or multiple string dead notes and much more this way. And you can also use it for big string skips like in the video below. Anyone here using the ring finger for slapping? Not sure if you can embed videos here?
https://www.youtube.com/watch?v=1GzV_j-0Ibk&ab_channel=NextLevelSlapBass